Slug casting machine



March 22, 1938. w. L. PETERSEN SLUG CASTING MACHINE F iled Oct. 51, 1936 s Sheets-Sheet 2 B WK INVENTOR Arm/2x512 W. L. PETERSEN- SLUG CASTING MACHINE 7 Filed Obt. 51, 1936 March 22, 1938.

3 Sheets-Sheet 3 oEofo I INVENTOR} ATTQR 5 Patented Mar. 22, 1938 PATENT QFFECE SLUG OASTENG MACHINE William L. Petersen, Springfield, N. Y., assignor to Mcrgenthaler Linotype Company, a corporation of New York Application October 31,

20 Claims.

This invention relates to slug casting machines, such as Linotype machines of the general organization represented in U. S. Letters Patent to O.

Mergenthaler, No. 436,532, wherein a melting pot s is arranged to deliver molten metal into a slotted mold and up against a composed line of matrices to'produce atype bar or slug bearing, on its edge type characters corresponding to the intaglio characters of the matrices. In these machines, the molten metal is introduced into the mold by means of a spring-actuated pump piston or plunger arranged'within the'pot and controlled in its action by a rotary cam which, as well known, makes onecomplete rotation for each cycle of operation of the machine. The cam is so shaped as normally to maintain the pump plunger in a raised position out of action, but at one portion of its circumference it is formed with a depression which at the proper time permits the plunger to descend under the influence of its actuating spring to force the metal into the mold, it being understood in this connectionthat the distance the plunger descends or its effective stroke is largely determined by the amount of metal it displaces rather than by the depth of the depression in the cam. Since the slugs produced in the modernv machines vary widely. in

size (both as regards length and thickness), it is evident that the effective stroke of the plunger will vary correspondingly, assuming, of course, that the metal be kept at a constant level within the pot. Thus, when casting short slugs of the thinner variety, the plunger descends only a short distance as compared with the distance it is required to travel when'casting long slugs of the thicker variety. In practice it has been found that this variable condition frequently leads to the casting of defective slugs. The dimculty is that oftentimes the actual casting period is tooshort to permit the molten metal to congeal or solidify before the return stroke of the pump plunger, which, under such circumstances, exerts a suction effect and draws some of the metal from the mold back into the pot. The condition becomes more aggravated in the case of the larger slugs which, not only require a greater volume of metal and therefore a greater time for cooling, but which in addition necessitate a longer efiective stroke of the pump plunger and correspondingly less time before itbegins its return stroke.

The present invention is intended to overcome these and other objections and contemplates automatic means for delaying the return stroke of the pump plunger for a predetermined interval after the mold has been filled with molten metal 1936, Serial N0. 108,559

to'allow additional time for the metal to. solidify before the pump pressure is removed. In the present embodiment, the machine is equipped with automatic means for disengaging the main driving clutch of the machine during the effective stroke of the pump plunger so as to arrest the rotation of its controlling cam, and with automatic means actuated by the pump plunger at a later period in its effective stroke for reengaging the driving clutch to restart the rotation of its controlling cam In this way a definite pause in the normal operation of the machine is created after the mold has been filled with molten metal, this pause corresponding to the time consumed by the plunger in moving from its mold filling position t the end of its effective stroke. In carrying out the invention the pump plunger is given a uniform effective stroke regardless of the size of the slug to be cast, the plunger being provided with a by-pass which will permit the escape of molten metal past the plunger throughout its effective stroke. Preferably, the size or area of the by-pass is variable in order to vary the time interval referred to, it being pointed out that the area of the by-pass should be greater in casting the smaller slugs. (which do not require so much time to congeal orsolidify) and lesser for the larger slugs (which require a longer time to congoal or solidify). In the present instance the bypass is formed in the pump plunger and is variaole by means of an adjusting device risingfrom the plunger above the level of the molten metal in the pot for ready accessibility.

In the accompanying drawings the invention has been shown merely in preferred form and by way of example as applied to a Linotype machine, but obviously many changes and alterations may be made therein and in'its mode of adaptation without departing from its spirit. Generally speaking, it is to be understood that the invention is not limited to any specific form or embodiment, except insofar as such limitations are specified in the appended claims.

Referring to the drawings:

Fig. l is a side elevation, partly in section, of the casting mechanism constructed in accord- -ance with the invention, and showing the parts in their normal position of rest;

Fig. 2 is a plan view of the pumpplunger and showing the plunger rod in section;

Fig. 3 is a vertical section taken through the pump plunger and showing the variable by-pass and the adjusting device associated therewith;

Fig. 4 is a view similar to Fig. 1, but showing the plunger as it approaches the end of its effective stroke and after the machine has been stopped;

Fig. 5 is a similar view showing the pump plunger at the end of its effective stroke and after restarting the machine;

Fig. 6 is an elevation of the main driving clutch of the machine with its actuating connections; and

Fig. 7 is a longitudinal section taken on the line 'l'l of Fig. 4.

In Fig. 1, the parts are shown in the relative positions they occupy just prior to the commencement of the slug casting operation, the slotted mold A carried by the rotary disc A being closed at the front by the composed line X, which is presented momentarily thereto by the first elevator B, and at the rear by the mouthpiece of the melting pot C, which contains a supply of type metal maintained in a molten condition by means of a suitable burner or heater (not shown). The pot C is formed with a throat or passage C through which the molten metal is forced into the mold by a spring-actuated plunger D, the latter being arranged to reciprocate within the pot well or cylinder C communicating with the throat C The plunger D is connected by means of a rod or link D to the long arm of a bell-crank lever D having a sleeve portion D journalled on a fixed transverse rod D of the machine frame and provided with an arm D extending laterally beneath a second lever D which is also journalled on the rod D and connected at its free end to a pull spring D The latter is anchored to the machine frame and actuates the plunger D through the connections just described. The shorter arm of the bellcrank D is provided with a roller D arranged to track upon the periphery of the usual rotary cam 13 fast to the main shaft of the machine. As well understood, the peripheral face of the cam D is concentric throughout, except at one portion of its circumference where it is cut away or formed with a depression D When the machine is at rest, the roller D is in contact with the concentric portion of the cam D", so that the plunger D is maintained in its raised or inoperative position, as shown in Fig. 1. This condition obtains until the casting period arrives, when the cam rotating in the direction indicated brings the downwardly sloping surface (1 of the depression D into engagement with the roller 13*, which then quickly descends along such surface toward the bottom of the depression, thus permitting the spring D to depress the plunger and force a charge of molten metal into the mold. In the present instance, the concentric portion of the cam D has been extended slightly, as at (1 so as to overlap the sloping portion (1 and thus correspondingly delay the depression of the plunger by the actuating spring, giving a quicker drop to the plunger than ordinarily. As the cam continues to rotate, the roller D is engaged sooner or later by the upwardly sloping surface d of the depression D and the parts thereby more gradually restored to their original condition to await the next casting operation.

The parts so far described, and their construction and mode of operation, are or may be the same as those embodied in the commercial Linotype machine and in themselves constitute no part of the present invention.

It will be understood that, during the slug casting period, the roller 13 will ordinarily seldom reach the bottom of the depression D due to the fact that the plunger D will be arrested in its descent at one level or another according to the volume of metal it displaces in effecting the cast. In the present instance, however, it is proposed to give a uniform efiective stroke to the plunger regardless of the size of slug to be cast so that it will always descend the same distance each time it is operated. Thus, at its lower end, the plunger is provided with an internally threaded portion D formed with a vertical port or aperture D extending through the bottom face of the plunger and a communicating lateral port D extending into the pocket D formed on the opposite face of the plunger for the reception of the actuating rod D A valve plug D in the form of a long adjusting screw rising above the molten metal in the pot, is screwed into the threaded portion D and serves to vary the area or size of the by-pass constituted by the ports D and D According to this arrangement, when the pump plunger D is actuated by the spring D it will descend quickly until the mold is filled with molten metal and then descend more gradually until it completes its full effective stroke, which means that the roller D will in all cases be allowed to reach the bottom of the depression D or as close to it as may be desired. The time consumed by the plunger in moving from its mold filling position to the end of its stroke may be varied by the adjustment of the screw valve D to suit conditions, it being desirable to prolong the period for the larger slugs and to shorten it for the smaller slugs. The variable by-pass therefore, in effect, constitutes a timing device which, as will subsequently appear, is utilized in determining the pause in the normal operation of the machine during the casting period.

The main shaft G of the machine, on which the plunger controlling cam D is mounted, is driven by a large gear wheel E meshing with a driving pinion E of an auxiliary shaft E which is equipped with the customary main driving clutch (see Rogers Patent No. 661,386) comprising a pulley E and clutch shoes E (Fig. 6). When the machine is at rest, the clutch shoes E are disengaged from the pulley E as shown in Fig. 6, but, as is well known, when the composed line is transferred into the first elevator B, the clutch shoes E are automatically engaged with the pulley E to inaugurate the normal single cycle of operation of the machine. Upon the completion of that normal cycle, the clutch shoes E are automatically disengaged to stop the machine. The operation of the clutch shoes E is efifected by the usual clutch shifter E In providing for the stopping and restarting of the machine during the casting period, these same clutch devices are utilized as will now be described. 7

Depending from the sleeve D of the pump operating lever D there is a long arm F carrying at its lower extremity an adjusting screw F which is arranged to cooperate with a slide F mounted in guideways formed in a block F fastened rigidly to the end of the main shaft G. Consequently, as the main shaft G is rotated, the slide F will be carried around with it. The slide F it will be observed is formed at one end with a cam piece F arranged to cooperate with a roller F carried at the upper end of a vertical lever F centrally pivoted to a fixed bracket F and carrying at its lower end a set screw F (see particularly Fig. 6) arranged to abut against one end of a rod F which is connected at its opposite end to the clutch shifter E The arrangement is such thatwhen the cam shaft G has been rotated far enough to bring the cam D to its pump releasing position, the cam piece F will engage the roller F and rock the lever F in a direction to disengage the main driving clutch, thereby stopping the operation of the machine. At this time, however, the spring D will pull the pump plunger downwardly on its eiifective stroke to fill the mold with molten metal, Fig. 4 showing the plunger on its way down and near the end of its stroke. In completing its effective stroke under the delaying influence of the variable by-pass formed therein, the plunger will ultimately assume the position shown in Fig. 5, and in doing so it will rock the lever F rearwardly and cause it to shift the slide F rearwardly, such rearward movement of the slide F moving the campiece F clear of the roller F (as shown in Fig. 5) and allowing the main driving clutch to be reengaged under the influence of its customary spring. "When this occurs, the operation of the machinewill be started againan'd the cam D in resuming its rotation will cause its sloping surface (2 to engage the roller I) and impart the return stroke to the pump plunger. During the return stroke of the pump plunger, the slide F will be restored to its original positionin the block F under the influence of a return spring F Ultimately, when the machine completes its normal cycle of operation, the parts will cometo rest in the position shown in Fig. 1.

It will now be seen that the desired delay in pumping stroke of the pump plunger and thereafter by reengaging the clutch to restart the machine as the plunger completes its effective stroke. a It will be observed that the time interval between the stopping and the restarting of the machine is controlled by the by-pass formed in the pump plunger, this by-pass permitting the metal to'escape past the plunger from the pressure chamber'into the supply chamber after the mold has been" filled with molten metal and allowing the plunger always to reach the end of its efiective stroke. It is not necessary, of course, to vary the by-pass for each different size of slug cast, the adjustable valve plug B being intended merely to fix the time'interval for slugs within certain ranges. For instance, in casting the smaller slugs, the by-pass may be fully opened to allow the plunger to completeits full effective stroke in the minimum time interval, whereas in casting the larger slugs, the area of the by-pass will be greatly diminished in order to increase the time interval, it being understood that in casting such larger slugs the mold filling position of the plunger will be much nearer its full stroke position. It is not essential that the by-pass in the plunger be variable because its area could be fixed with reference to the time interval required for the casting of the larger slugs, such slugs being the ones which require the delay in the casting period. By var ing the by-pass, how ever, the time interval may be out down for the smaller slugs which do not require the same delay in the casting period, and which without the variable lay-pass wouid evenhave a greater period due to the fact that the mold filling posi tion of the plunger is farther removed from its final eiIective stroke position. In practice, as above intimated, the adjustment of the try-pass will be made for. different ranges of slug sizes and 7 effective stroke.

will be calculated to give approximately the same time interval for the casting of all sizes.

Having thus described my invention, what I claim is:

1. In a slug casting machine, the combination of a mold, a pump plunger for filling the mold with molten metal under pressure, and automatic means for creating a pause in the normal operation of the machine after the mold has been filled with molten metal but before the machine has completed its normal cycle to allow addition al time for the metal to solidify before the pump pressureis removed.

2. In a slug casting machine, the combination of a mold, a pump plunger for filling the mold with molten metal under pressure, and automatic means for stopping the machine during the efi'ective stroke of the plunger and for restarting the machine at a predetermined interval after the plunger has filled the mold but before the machine has completed its normal cycle, whereby additional time is allowed for the molten metal to solidify before the plunger begins its. return stroke.

3. In a slug casting machine, the combination of a mold, a pump plunger for filling the mold with molten metal under pressure, said plunger having a uniform effective stroke regardless of the size of the mold cavity, and automatic means for creating a pause in the normal operation of the machine after the mold has been filled with molten metal but before the machine has completed its normal cycle, said pause corresponding to the time consumed by the plunger in moving from its mold filling position to the end of its 4. In a slug casting machine, the'combination of a mold, a pump plunger for filling the mold with molten metal under pressure, said plunger having a uniform effective stroke regardless of the size of the mold cavity, and automatic means for stopping the machine at the beginning of and then restarting it at the end of the efiective stroke of the pump plunger.

. 5. In a slug casting machine, the: combination of a melting pot containing a pump well, a pump plunger arranged to reciprocate in said well, a by-pass to permit the escape of molten metal from the pressure chamber into the supply chamber of the pot during the effective stroke of the pump plunger, and automatic means for first stopping and then restarting the machine at respectively different periods in the effective stroke of the pump plunger, the time interval between the two periods being predetermined by the area effective stroke, and automatic means for first stopping and then restarting the machine at respectively different periods in the effective stroke of the pump plunger, the time interval between the two periods being predetermined by the area of the by-pass.

7 In a slug casting machine, the combination of a melting pot containing a pump well, a pump plunger arranged to reciprocate in said well, a

by-pass to permit the escape of molten metal from the pressure chamber into the supply chamber of thepot during the effective stroke of the pump plunger, means for automatically stopping the machine at the beginning of the effective stroke of the pump plunger, and means actuated by the pump plunger at the end of its effective stroke for restarting the machine.

8. In a slug casting machine, the combination of a melting pot containing a pump Well, a pump plunger arranged to reciprocate in said well, a ny-pass formed in said plunger to permit the escape of molten metal past the same during its efiective stroke, means for automatically stopping the machine at the beginning of the effective stroke of the pump plunger, and means actuated by the pump plunger at the end of its effective stroke for restarting the machine.

9. In a slug casting machine, the combination of a melting pot containing a pump well, a pump plunger arranged to reciprocate in said well, a by-pass to permit the escape of molten metal from the pressure chamber into the supply chamber of the pot during the efiective stroke of the pump plunger, automatic means for first stopping and then restarting the machine at respectively different periods in the effective stroke of the pump plunger, the time interval between the two periods being predetermined by the area of the by-pass, and means for varying the area 01' the by-pass toincrease or diminish the time interval between the machine stopping and restarting periods.

10. In a slug casting machine, the combination of a melting pot containing a pump well, a pump plunger arranged to reciprocate in said well, a by-pass formed in said plunger to permit the escape of molten metal past the same during its efiective stroke, automatic means for first stopping and then restarting the machine at respec tively diiierent periods in the effective stroke of the pump plunger, the time interval between the two periods being predetermined by the area of the by-pass, and means for varying the area oi the by-pass to increase or diminish the time interval between the machine stopping and restarting periods.

11. In a slug casting machine, the combination of a melting pot containing a pump well, a pump plunger arranged to reciprocate in said well, a by-pass to permit the escape of molten metal from the pressure chamber into the supply chamber of the pot during the effective stroke of the pump plunger, means for automatically stopping the machine at the beginning of the effective stroke of the pump plunger, means actuated by the pump plunger at the end of its effective stroke for restarting the machine, and means for varying the area of the by-pass to increase or diminish the time interval between the machine stopping and restarting periods.

12. In a slug casting machine, the combination of a melting pot containing a pump well, a pump plunger arranged to reciprocate in said well, a Icy-pass formed in said plunger to permit the escape of molten metal past the same during its eiiective stroke, means for automatically stopping the machine at the beginning of the effective stroke of the pump plunger, means actuated by the pump plunger at the end of its effective stroke for restarting the machine, and means for varying the area of the by-pass to increase or diminish the time interval between the machine stopping and restarting periods.

13. In a slug casting machine, the combination of a melting pot containing a pump well, a pump plunger arranged to reciprocate in said well, a by-passto permit the escape of molten metal from the pressure chamber into the supply chamber of the pot during the effective stroke of the pump plunger, and an adjusting device for varying the area of the by-pass, said device being arranged within the supply chamber of the pot and rising above the level of the molten metal therein for ready accessibility.

14. In a slug casting machine, the combination of a melting pot containing a pump well, a pump plunger arranged to reciprocate in said well, a by-pass formed in said plunger to permit the escape of molten metal past the same during its effective stroke, and an adjusting device carried by the pump plunger for varying the area of the by-pass, said device being arranged within the supply chamber of the pot and rising above the level of the molten metal therein for ready accessibility.

15. In a slug casting machine equipped with a main driving clutch, the combination of a mold, a pump plunger for filling the mold with molten metal under pressure, and automatic means for disengaging the main driving clutch before and then reengaging it after the mold has been filled with molten metal to allow additional time for the molten metal to solidify before the pump pressure is removed.

16. In a slug casting machine equipped with a main driving clutch, the combination of a mold, a pump plunger for filling the mold with molten metal under pressure, and automatic means for disengaging the main driving clutch during the eiicctive stroke of the pump plunger and for reengaging the clutch at a predetermined interval after the pump plunger has filled the mold, whereby additional time is allowed for the molten metal to solidify before the pump plunger begins its return stroke,

17. In a slug casting machine, the combination of a melting pot containing a pump well, a springactuated plunger arranged to reciprocate in said well, a rotary cam for controlling the active stroke of the plunger, and automatic means for stopping the rotation of the cam at the beginning and then restarting its rotation at the end of the effective stroke of the pump plunger.

18. In a slug casting machine, the combination of a melting pot containing a pump well, a springactuated plunger arranged to reciprocate in said well, a rotary cam for controlling the active stroke of the plunger, means for automatically stopping the rotation of the cam during the effective stroke of the pump plunger, and means actuated by the pump plunger at a later period in its efiective stroke for restarting the rotation of the cam.

19. In a slug casting machine, the combination of a melting pot containing a pump well, a springactuated plunger arranged to reciprocate in said well, a rotary cam for controlling the active stroke of the plunger, a main shaft on which the cam is mounted, driving means for the shaft including a spring-actuated clutch, means for automatically disengaging the clutch during the effective stroke of the pump plunger, and means actuated by the pump plunger at a later period in its eiiective stroke for reengaging the clutch.

20. In a slug casting machine, the combination of a mold, a pump plunger for filling the mold with molten metal under pressure, and automatic means for delaying the return stroke of the pump plunger for a predetermined int rval after the mold has been filled with molten metal to allow additional time for the metal to solidify before the pump pressure is removed.

WILLIAM L. PETERSEN. 

